My 390 has been running like crap to say the least for the last month or so. I only drive it about once a week so it doesn't see very many miles right now. On cold start up, it would start, high idle for about 10 sec's and then sound just like it was loading up w/ fuel. So being exceedingly pissed off, I thought that I would need to put a kit in my 1 year old carb! Well, the other day I went to crank it up and it wouldn't hardly run worth crap- only hitting about 3-4 cylinders with the throttle halfway. But it was missing the same cylinders at the same time every time around so I started thinkin ignition. Pulled the dizzy cap to find all kinds of tracing and one lead actually has what looks like a big o'll blob of grease build up on it and 3 others had whitish/blue chalk buildup on them. So new cap I went and it runs like it should but where did all this come from?? 4 of the other leads had typical charcoal tracing on them but why are the others like this? Will cheap wires or wires not allowing juice to flow properly do something like this? They're 8mm advance wires for a 460 (b/c I went to the larger cap) that I bought cheap at the time b/c I was experimenting w/ my ignition setup. The cap is a bluestreak brass lead cap. It's only been on there almost 2 years and maybe 10,000 miles at the most! The rotor looks fine.

 

Moisture will do that every time and letting the engine set a lot causes the problem. The cure to go out and start and warm up the engine more often, even if you don't drive it. Or put it in a heated garage.